Impulse clutch



March 18, 1941. E MARSH IMPULSE CLUTCH Filed April 6, 1938 2Sheets-Sheet l INVENTOR. 051.055 MARSH ATTORNEY.

March 18, 1941. D MARSH 2,235,379

- IMPULSE CLUTCH Filed April 6, 1958 2 Sheets-Sheet 2 Y .DELOS E MARSHATTORNEY.

Patented Mar. 18, 1941 UNITED STATES TET OFFICE 17 Claims.

This invention is an impulse clutch and has for its object to apply adriving force to a driven element and then automatically disengage thedriving connection after predetermined movement of the driven element.

It is a further object of the invention to limit movement of the drivenelement at each actuation thereof, and to position the parts forreengagement of the driving connection at the end of each movement ofthe driven element.

It is a still further object of the invention to suddenly apply thedriving force and to automatically disengage the driving connectionafter a brief interval of engagement, so as to provide a brief intervalof movement for the driven element, at the end of which the parts areagain in position for engagement of the driving connection. Theinvention is thus particularly adapted for applying a series of sudden,intermittent impulses to a driven element, with the series of impulsesfollowing one another with great rapidity. The invention may thus beadvantageously employed in apparatus operated by and/or controllingsound, light or electrical waves of high frequency.

It is a still further object of the invention to apply a relativelystrong driving force to" the driven element, and to control engagementof the driving connection by a relatively weak force. The invention isthus particularly adapted for controlling the driving connection by aforce such as a weak electrical current, for actuating the drivenelement by a relatively strong driving force. The invention may thus beadvantageous- 35 1y employed in electrical relays and the like, with aweak line current controlling engagement of the driving connection,which in turn applies a relatively strong force for controlling a localcircuit.

It is a particular object of the invention to utilize movement of thedriven element for interrupting a beam of light which in turn controlsan electrical circuit, thereby controlling the circuit withoutmechanical engagement and disen- 45. gagement of electrical contacts insaid circuit, and thus providing an extremely sensitive control which isparticularly applicable'to an electrical relay.

It is a still further object of the invention to positively arrestmovement of the driven element upon disengagement of the drivingconnection, Without binding action opposing subsequent reengagement ofthe driving connection. The driving connection is thus particularlyadapted 55. for control by an extremely weak force and for readyengagement and disengagement so that the series of impulses imparted tothe driven element may follow one another with great rapidity.

Further objects of the invention will be readily understood from thefollowing description of the accompanying drawings, in which:

Fig. 1 is a side elevation of the invention embodied in a photo-electricrelay.

Fig. 2 is a plan view of the same.

Fig. 3 is a detail section on the lines 33 of Fig. 1.

Fig. 4 is a detail section on the line 4-4 of Fig. 3.

Fig. 5 is a View similar to Fig. 3, showing a modified construction.

Figs. 6 and 7 are detail sections on the lines 66 and T-l respectivelyof Fig. 5.

Fig. 8 is a side elevation of the invention, embodied in a modifiedconstruction wherein the driven element provides a step-by-stepmechanical drive for any desired apparatus.

Fig. 9 is a plan View of that embodiment of the invention which is shownat Fig. 8.

Fig. 10 is a detail section on the line lfl-lfl of Fig. 9.

Fig. 11 is a plan view of the detail shown at Fig. 10.

Fig. 12 is a vertical section on the line 2-42 of Fig. 10.

The invention is applicable to any apparatus wherein a relatively strongdriving force is to be applied for imparting a series of impulses to adriven element, with application of the driving force controlled by anysuitable means, e. g. a manual or electro-magnetic control, and withmovement of the driven element employed for any desired purpose, e. g.for actuating a shutter, controlling an electrical circuit, causingmovement of an indicator, etc.

The invention is particularly applicable to electrical relays, and moreparticularly a photoelectric relay whereby a weak line current may beemployed for controlling applicationof a relatively strong driving forcefor actuating a shutter, with the shutter interrupting a light beamwhich in turn controls a photo-electric cell for making and breaking alocal circuit. The invention is also particularly applicable to anelectrical indicator whereby a weak line current may be employed forcontrolling application of a relatively strong driving force forstep-by-step rotation of a driven element in accordance with weakimpulses in the line, circuit, so as to correspondingly actuate anindicator which is operated by the driven element.

The invention embodies a driving element and a driven element, and adriving connection therebetween. The driving element may be driven byany suitable source of power, and in the illustrated embodiments of theinvention the driving element is a rotatable element driven by anelectric motor. The driving connection may be manually or otherwisecontrolled, and in the illustrated embodiments of the invention thedriving connection is controlled by an electro-magnet. The drivingconnection is automatically disengaged after predetermined movement ofthe driven element, with the driven element limited to predeterminedmovement after said disengagement; and in the illustrated embodiments ofthe invention this predetermined movement of the driven element is anarc of oscillation, or an arc of step-b'y-step rotation.

The driving connection is arranged so that after predetermined movement.of the driven element the parts are again in position for engagement ofthe driving connection. An illustrated embodiment of this arrangementincludes an oscillating pawl, one end of which is engaged by the drivingelement for swinging the pawl and the driven element in one directionand then automatically disengaging said pawl-end from the drivingelement after predetermined arcuate movement of the driven element, withsaid -arcuate movement of the pawl positioning the same ready forengagement of its opposite end by the driving element for swinging thepawl and the driven element in the opposite direction. Anotherillustrated embodiment includes a pawl, one circumferential portion ofwhich is engaged by the driving element for rotating the pawl and thedriven element and then automatically disengaging said pawl from thedriving element after predetermined rotation of the driven element, withsaid rotation of the pawl positioning the same ready for engagement ofanother portion of the pawl by the driving element for again rotatingthe pawl and the driven element a predetermined distance in the samedirection as that first mentioned.

Movement of the driven element may be employed for actuating any desiredmechanism. In an illustrated embodiment, movement of the driven elementactuates a control for an electrical circuit and while this control maybe of any desired type, such as mechanical engagement and disengagementof electrical contacts, the invention is particularly applicable and isillustrated in connection with a photo-electric control adapted forinterruption of a light beam by movement of the driven element, with thelight beam controlling a photo-electric cell which in turn makes andbreaks an electrical circuit. In another illustrated embodiment,movement of the driven element providesa drive for any desiredapparatus, e. g. an indicator which is thus actuatedin accordance withimpulses imparted to the driven element.

Referring to Figs. 1 to 4, the invention is embodied in a photo-electricrelay in which the driving connection is electro-magnetically controlledand the driven element is oscillated for swinging .a shutter so as tointercept a light beam which controls a photo-electric cell for makingand breaking an electrical circuit. The electrical circuit is thuscontrolled without mechanically engaging and disengaging electricalcontacts in said circuit, and the relay is thus adapted for operation athigh frequency and by a weak current for energizing the electromagneticcontrol for the driving connection.

As an instance of this arrangement, the driving element is shown astransversely spaced friction discs i-Z which are fixed for rotation witha shaft 3. The shaft 3 is driven by an electric motor 4. The drivenelement is shown as a pawl 5 medially pivoted on an arm 6 so that it ispositioned between the transversely spaced discs l-2. The arm ii isfixed on a shaft 1 which is adapted for oscillation so as totransversely shift the arm for positioning one end or the other of thepawl 5 for engagement by one or the other of the discs 2, while at thesame time positioning the other end of the pawl so that it clears theother of said discs. The shaft 1 is oscillated by an armature pole piece8 which is fixed on said shaft and which extends between the pole pieces9 of electrical coils ill. The coils ill and a permanent magnet llcooperate to form an clectromagnet which is included in an electricalcircuit (not shown), and which is arranged whereby an alternatingcurrent in the circuit oscillates the armature pole piece 8 fortransversely shifting the arm 6 so that one end of the pawl 5 is engagedby the driving element each time the current is in one direction,

and the other end of the pawl is engaged by the driving element eachtime the current is in the opposite direction.

Engagement of one end of the pawl by the driving element swings the pawla limited distance in one direction, and engagement of the other end ofthe pawl by the driving element swings the pawl a limited distance inthe opposite direction. A shutter i5 is fixed to the pawl foroscillation therewith, and its swinging movement in each directionintercepts and then clears a light beam. This light beam may be formedby focusing a source of light (not shown) so as to project a light beamA onto a mirror I6, whereby the beam is reflected as a light beam Bwhich is intercepted by the oscillating shutter i5. The light beam B isdirected against a photo-electric cell I! which is included in anelectrical circuit (not shown), whereby the photo-electric cell makesand breaks this circuit each time the shutter 15 is swung in onedirection or the other. e

The electrical circuit which controls the electromagnet lvl-H may be aweak line current, and the electrical circuit which is controlled by thephoto-electric cell ll may be a local circuit. The weak line currentthus controls the local circuit without mechanically engaging anddisengaging electrical contacts in said local circuit.

The driving connection between the pawl 5 and the friction discs l-2 isarranged as follows:

Those portions of the pawl which extend in opposite directions from itsmedial pivot are angularly disposed as shown at Fig. 3, and the ends ofthe pawl comprise angularly projecting friction-ends 20-2l adapted torespectively engage similarly angularly disposed friction surfaces 2223of the discs l-2. When the pawl has been swung to a'position where itsend 20 is substantially normal to but spaced from its cooperating discl, and the arm 5 is then transversely shifted to the left as viewed atFig. 3, the pawl-end 20 is moved into engagement with the frictionsurface 22 of the disc I and the pawl-end 2| is moved clear of itscooperating disc 2 so that it is free to swing without engaging saiddisc. The resulting driving connection 22-28 swings the pawl 5 on itsmedial pivot to the position shown at Fig. 3, by rotation of the drivingelement l2 in the direction indicated by the arrow G. Dining thisswinging movement the contacting surfaces 22-20 tend to disengage due tothe curvature of the surface 22 and the arcuate swing of the pawl-end20, but continued transverse shifting of the arm 6 causes the pawlend 20to overlap the cooperating friction surface 22 as shown at Fig. 4, so asto compensate for this tendency and thus maintain the drivingengagement.

Adjustable stops 24-25 are provided at the respective sides of the arm6, and the stop 24 provides a predetermined limit for the aforementionedtransverse shifting of said arm. The driving force which has beenimparted to the pawl-end '20 then continues swinging movement of saidpawl-end, as a result of which the cooperating surfaces 22-20 areautomatically disengaged after any desired interval of enga ment asdetermined by adjustment of the stop 24. Adjustable stops 26-21 areprovided for the respective pawl-ends 20-2 I, and the stop 26 limitsswinging movement of the pawl-end 20 after the driving connection hasbeen thus disengaged, whereby adjustment of the stop 26 provides anydesired limit for the swinging movement of the pawl. The pawl-end 20 isthen held against swinging movement in the reverse direction, since anysuch tendency would reengage the driving connection 22-20 and thus againswing said pawl-end clear of its cooperating driving disc.

The limited swinging movement of the pawlend 20 as thus described and asshown at Fig. 3, swings the opposite pawl-end 2| in the reversedirection to a position substantially normal to but spaced from itscooperating disc 2, ready for engagement of the pawl-end 2| with thefriction surface 23 of its cooperating disc 2 when the arm 6 is thentransversely shifted to the right as viewed at Fig. 3. When the arm 6 isthus shifted to the right, the pawl-end 20 is moved clear of itscooperating disc I so that it is free to swing without engaging saiddisc, and the driving connection 23-2l then swings the pawl in thedirection opposite to that previously described, with continuedtransverse shifting of the arm 6 maintaining the driving connection23-2| as previously described, until the arm 6 engages the stop 25. Thedriving connection is then automatically disengaged as previouslydescribed, and swinging movement of the pawl is then arrested by thestop 21. The pawl is then held against reverse swinging movement, sinceany such tendency would reengage the driving connection 23-2l so as toagain swing the pawlend 2| clear of its cooperating disc 2.

The limited swinging movement of the pawlend 2| as thus described,swings the opposite pawl-end 20 in the reverse direction to a positionsubstantially normal to but spaced from its cooperating disc I, readyfor reengagement of thedriving connection 22-20 when the arm 6 is againtransversely shifted to the left a viewed at Fig. 3. l

The pawl-ends 20-2| engage their cooperating stops 26-21 withoutfrictional binding enfrictionally bind this abutment.

respective stops are preferably disposed so that the plane of abutmentbetween either pawl-end and its cooperating stop is substantiallyparallel to the plane of transverse shifting of the arm 6 (as shown by.the pawl-end 20 and the stop 2 at Fig. 3).

By thus eliminating frictional binding engagement at the abutment ofeither pawl-end against its cooperating stop, with the abutment in. atransverse plane as described, the arm ,6 is adapted for transverseshifting to engage the driving connection at the other pawl-end with nobinding action opposing its free movement. The arm is thus adapted forrapid transverse shifting by a weak force, thereby adapting the devicefor imparting a series of impulses to the driven element, with theseries of impulses following one another with great rapidity.

When the driving connection 22-20 swings the pawl to the position shownat Fig. 3, the shutter I5 is swung from the position shown by dottedlines to that shown by full lines, and when the driving connection 23-2lswings the pawl in the opposite direction the shutter I5 is swung fromthe position shown by. full lines to that shown by dotted lines. At eachswinging movement of the pawl 5 in one direction or the other, theshutter l5 thus intercepts and then again clears the light beam B foractuating the photo-electric cell l7. Each impulse of an alternatingcurrent in the circuit which includes the electro-magnet and whichcauses the arm 6 to be transversely shifted in one direction or theother, thus results in a driving force being applied whereby the circuitwhich is controlled by the photo-electric cell I1 is made and broken insynchronism with the impulses of said alternating current.

The modification of the inventionshown at Figs. to 7 may be embodied inthe same structure as previously described, but provides a slightlydifferent driving connection between a driving element which is rotatedby the shaft 3 and a cooperating pawl 5 which carries a shutter I5 andwhich is medially pivoted on the transversely shiftable arm 6.

In this construction, the discs I -2 are fixed for rotation with thedrive shaft 3, but instead of being friction discs as previouslydescribed, these discs are toothed ratchet discs. The cooperating pawl 5is positioned between the discs I -2 and its portions which project inopposite direction from its medial pivot are angularly disposed aspreviously described. The ends 20%- 2F of the pawl are adapted forrespective engagement by the toothed ratchet discs I -2 faces extendingan appreciable distance radially of the discs and of graduallyincreasing width toward the outer ends of the teeth as shown at 33 atthe left of Fig. 6.

The parts are so arranged that when the pawl 5 has been swung to aposition where the pawlend 20 is substantially normal to but spaced fromits cooperating disc 1, and the arm, -6 is then transversely shifted tothe left as viewed at Fig. 5, the pawl-end 20 is engaged by a tooth 30of the disc l while the pawl-end 2| is moved clear of its cooperatingdisc '2 so that it is free to swing without engaging the teeth of saiddisc. 3IJ'MI swings the pawl 5 on its medial pivot to the position shownat Fig. 5, by rotation of the driving element l -2 in the directionindicated by the arrow C. During this swinging movement, the pawl-end 28shifts relativev to its cooperating tooth 30 so as to tend to clear thetooth and thus disengage the driving connection, due to the arcuateswing of the pawl-end and the arcuate path of travel of the tooth.

To compensate for this tendency and thus maintain the drivingconnection, the parts are arranged whereby initial engagement of thepawl-end with a tooth, is at that narrower portion of the tooth which isat .the radially inner end of its tooth surface. As the disc i isrotated, the pawl-end Zfi is'thus engaged by portions of the toothsurface which are successively further and further from its inner end(due to the arcuate path of travel of the tooth), but the length of thetooth is such as to maintain engagement during thismovement. In the samemanner, swinging movement of the pawl results in its end 26 beingshifted transversely of the engaged tooth (due to the arcuate swing ofthe pawl), but the increasing width of the tooth surface toward itsouter end, as shown at 33, maintains engagement of the drivingconnection for an appreciable interval before the pawlend is finallyswung clear of the tooth 30.

The adjustable stops 24-25 (previously described) limit transverseshifting of the arm 6, and the stop 24 is adjusted so that transverseshifting of the arm provides any desired initial overlapping of thepawl-end 28* upon a tooth 30, so that swinging movement of the pawlshifts the pawl-end 2B clear of the edge 33 of the tooth and thusdisengages the driving connection, after any desired interval ofmovement. Adjustable stops 26 -21 are provided for the respectivepawl-ends m -2|, and the stop limits swinging movement of the pawl-end28 after the driving connection has been thus disengaged, wherebyadjustment of the stop 26 provides any desired limit for the swingingmoveinlent which has been imparted to the pawl by the driving connectiontill-2W. The pawlend Ml is then held against swinging movement in thereverse direction, since any such tendency would reengage the drivingconnection 3020 and thus again swing said pawl-end clear of the toothwhich has engaged the same.

The limited swinging movement of the pawlend 20 as thus described and asshown at Fig. 5, swings the opposite pawl-end H in the reverse directionto a position substantially normal to but spaced from its cooperatingdisc 2, ready for engagement of the pawl-end 21 by a tooth 3| of itscooperating disc 2 when the arm 6 is transversely shifted to the rightas viewed at Fig. 5. When this driving connection is made, the pawl-endMl is moved clear of its cooperating disc I so that it is free to swingwithout engaging the teeth of said disc, and the driving connection 3l2lthen swings the pawl in the direction opposite to that previouslydescribed. Transverse shifting of the arm 6 to provide this drivingconnection 3IZI is limited by the adjustable stop 25, and therefore, aspreviously described, provides any desired overlapping of the pawl-end2| upon the abutment surface of a tooth 3|, for swinging the pawl-endclear of the tooth and thus automatically disengaging the drivingconnection after any desired interval of movement. Upon release of thedriving connec- The resulting driving connection.

tion, swinging movement of the pawl is arrestedby the stop 21*. The pawlis then held against reverse swinging movement, since any such tendencywould reengage the driving connection 31- Zi so as to again swing thepawl-end 2| clear of the teeth. of its cooperating disc 2 The limitedswinging movement of the pawlend 2| as thus described, swings theopposite pawl-end 20 in the reverse direction to a positionsubstantially normal to but spaced from its cooperating disc IF, readyfor reengagement of the driving connection 3ll2ll when the arm 6 isagain transversely shifted to the left as viewed at Fig. 5.

The abutment of the pawl-ends fil --21 against their respective stops 26*=-2'l produces no frictional binding engagement, the drivingconnection having been disengaged when such abutment is made so thatthere is no force tending to bind said abutment, and the surfaces 8|] ofthe pawl-ends which engage the stops being disposed so that the plane ofabutment is substantially parallel to the plane of transverse shiftingof the arm 6. The arm 6 is thus adapted for-transverse shifting toengage the driving connection at the opposite pawl-end with no bindingaction opposing its free movement, thereby adapting the device forcontrol by a weak force, and also adapting it for imparting a series ofrapid impulses to the driven element.

The pawl 5 is thus swung in one direction and then the other bytransverse shifting of the arm 6 in one direction and then the other;and at each swinging movement of the pawl, the shutter 15* firstintercepts and then clears the light beam B for controlling aphoto-electric cell as previously described.

Referring to Figs. 8 to 11, th invention is embodied in a constructionin which the driving connection is electro-magnetically controlled aspreviously described, and the driven element is rotated a predetermineddistance at each engagement of the driving connection so as to provide adriving means for any desired apparatus, e. g. an indicator. Astep-by-step rotation is thus imparted to the driven element inaccordance with the electrical impulses which energize theelectro-magnetic control for the driving connection, therebycorrespondingly actuating an indicator or th like which is operated bythe driven element.

As an instance of this arrangement, the driving element is shown asfriction discs l -2 which are fixed for rotation with a shaft 3 theshaft being driven by an electric motor 4*. The driven element is shownas friction discs 404l, fixed for rotation with a shaft 42 and defininga peripheral, tapering tongue 43, an arcuate portion of which is adaptedfor reception in an arcuateportion of a cooperating peripheral, taperinggroove 44 which is formed by tapering, peripheral surfaces of the discs-2'. The shaft 42 is adapted for axial shifting in one direction or theother, i. e. transversely of the cooperating peripheral tongue andgroove 4344, so that each axial shifting of the shaft engages and thenautomatically disengages a driving connection at the cooperatingperipheral tongue and groove.

The shaft 42 is axially shifted by an arm 6 which is adapted fortransverse shifting by an arrangement the same as that previouslydescribed. This construction includes an oscillatingshaft I on which thearm 6* is fixed,.with the shaft 1 oscillated by an armature pole piece 8which extends between the pole pieces 9 of an electro-magnet lo -l l Theelectro-magnet is controlled by an electrical circuit (not shown), andis arranged so that an alternating current in the circuit oscillates thearmature pole piece 8 for transversely shifting the arm 6* and therebyaxially shifting the shaft 42, so that the driving connection is madeand then automatically disengaged each time the current is in onedirection, and is then reengaged and again automatically disengaged eachtime the current is in the opposite direction.

Each engagement of the driving connection rotates the shaft 42 apredetermined limited distance in the same direction; and an operatingmeans, shown as a gear 46 is fixed on the shaft 42 for rotationtherewith. Step-by-step rotation of the shaft 42 and the gear 46 thusprovides a step-by-step drive for any desired apparatus (not shown), e.g. an indicator which is adapted for movement relative to a cooperatingdial. Electrical impulses in the circuit which controls theelectro-magnet "l -li thus cause corresponding step-by-step movement ofthe indicator or other device which is actuated bythe gear 46.

The driving connection at the cooperating peripheral tongue and groove4344 is arranged as follows:

Contact surfaces of the discs 404l (which define the peripheral tongue43) are each interrupted by one or more low spots; and the low spots ofthe respective discs are circumferentially offset relative to oneanother, so that when the discs 494l are turned to a position where alow spot of either one of the discs is received in the groove 44, anon-interrupted portion of the contact surface of the other disc isreceived in said groove. The number of low spots on the discs 404|determine the arc of step-by-step rotation of the shaft 42 at eachengagement of the driving connection, and such number of low spots maybe employed as to provide any desired arc of rotation. In theillustrated embodiment, the shaft 42 is adapted for rotation through anarc of 90 at each engagement of the driving connection. For this purposea pair of diametri-- cally opposite low. spots 48 are provided on thedisc 40, thereby defining a pair of arcuate contact surfaces and a pairof diametrically opposite low spots 49, which are circumferentiallyoffset 90 relativ to the low spots 48, are provided on the disc 4|,thereby defining a pair of arcuate contact surfaces 5|.

Stops are provided for arresting rotation of the shaft 42 each time oneof the low spots 48 or 49 is received in the groove 44, and said stopsare arranged so as to again release the shaft 42 for further rotationwhen the arm 6* is next transversely shifted. In the illustratedembodiment, two of these stops are provided as shown at 5253, and arespaced axially of the shaft 42 and are fixed for rotation therewith. Thestops are mounted on the shaft 42 medially of their length so that eachprojecting end of each stop forms a stop element, and the stops 52--53are circumferentially offset 90 from one another.

The arm 5 is adapted for transverse shifting between the stops 52-53,below the shaft 42. When the arm is transversely shifted in onedirection as shown at Fig. 11, it clears the stop 53 and one end or theother of the stop 52 is adapted to rest upon the arm for arrestingrotation of the shaft 42, with one or the other of the low spots 48received in the groove 44; and

when the arm 6* is transversely shifted in the direction opposite tothat shown at Fig. 11, it clears the stop 52 and one end or the other ofthe stop 53 is adapted to rest upon the arm for arresting rotation ofthe shaft 42, with one or the other of the low spots 49 received in thegroove 44.

A projection 54 at the end of the armli engages the side of the stop 52for axially shifting the shaft 42 in the direction indicated by thearrow F, when the arm 6 is transversely shifted as shown at Fig. 11; andwhen the arm 5* is transversely shifted in the opposite direction theprojection 54 engages the side of the stop 53 for axially shifting theshaft 42 in the opposite direction. The projection 54 extends above theupper surface of the arm 6', so that as. the shaft 42 is rotated untilone or the other of the stops 5253 rests upon the arm, the projection 54maintains pressure against the side of said stop for axially shiftingthe shaft. The bearings 56 for the shaft 42, permit axial shifting ofsaid shaft, and include stops 5'l58 for limiting said axial shifting,with said stops adjustable as shown at 59.

The bearings of the shaft 3' which carries the friction disc-s l 2 areshown at B0, and are preferably yieldable bearings tensioned by springs6| so as to maintain a friction drive at the tongue and groove 4344 butadapted to yield for cushioning engagement of said drive. The tens-ionof the springs may be adjusted by bolts 62, 7'

and a flexible coupling 63 is provided between the shaft 3 and the motor4 to compensate for yielding of the bearings 69.

Operation of the driving connection 4344 will be explained, assuming theparts to be in their position opposite to that illustrated at Fig. 11,and in which position the parts are arranged as follows:

The arm 6 has been transversely shifted in the direction opposite tothat indicated by the f arrow F, so that the projection 54 has engagedthe side of the stop 53 and has axially shifted the shaft 42 in thedirection opposite to that indicated by said arrow and to its limit ofmovement as determined by the stop 58, and the shaft 42 has been rotatedin the direction of the arrow G until an end of the stop 53 rests uponthe arm- Y positionof the shaft 42. The driving connection is thusdisengaged and the shaft 42 is stationary at a limit of rotary movementdetermined by abutment of the stop 53 against the arm 6.

When the arm 6 is thentransversely shifted to the position shown at Fig.11, it clears the stop 53, and its projection 54 engages the side of thestop 52 so as to axially shift the shaft 42 in the direction of thearrow F. That portion of the contact surface 50 of the disc which is inthe groove 44 is thus engaged by the disc l so as to provide africtional driving connection, engagement of which is cushioned by thesprings B I, and whereby rotation of the discs l --2 in the direction ofthe arrow H, then rotates the discs 40--4| and the shaft 42 in thedirection of the arrow GQ The low spot 49 of the disc 4! which is in thegroove 44 is thus swung clear of said groove and a portion of a contactsurface 5i of said disc is received in said groove and is engaged by thedisc Fig. 11.

2*, while the contact surface 50 of the disc 48 is still engaged by thedisc l Rotation of the shaft 42 is thus continued until a low spot ofthe disc 40 enters the groove 44, which will be just prior to rotationof the shaft 42.

Continued transverse shifting of the arm 6 then continues axial shiftingof the shaft 42 in the direction of the arrow F, with this continuedaxial shifting of the shaft made possible by the space which has beenformed between the low spot 48 of the disc 40 and the cooperatingsurface of the groove 44. This continued axial shifting of the shaftdisengages the contact surface 5| of the disc 42 from the cooperatingsurface of the groove 44, but said axial shifting of the shaft isarrested by the stop 51, while the low spot 48 of the disc 40 is stilldisengaged from the cooperating surface of the groove 44, as shown atThe driving connection between the discs l 2 and the discs 4il4| is thusdisengaged, with said disengagement occurring just prior to completionof 90 rotation of the shaft 42. The driving force which has beenimparted to the shaft 42 then continues rotation of the shaft untilarrested by the stop 52 engaging the upper surface of the arm 6 theparts being relatively arranged whereby the shaft is thus fixed againstfurther rotation when it has been turned exactly 90, with the low spot48 of the disc 40 and the contact surface 5| of the disc 4| stillreceived in the groove 44. The position of the parts is then as shown atFig. 11, with rotation of the shaft 42 having rotated the gear 46through an arc of 90.

The parts are then in position ready for reengagement of the drivingconnection by transversely shifting the arm 6' in the opposite directionso as to axially shift the shaft 42 in the direction opposite to thatindicated by the arrow F.

By such transverse shifting of the arm 6 it is moved clear of the stop52 so that the shaft 42 is again free to rotate, and the contact surface5| of the disc 4| which is in the groove 44 is thus engaged by thecooperating disc 2" so as to provide a frictional driving connection,engagement of which is cushioned by the springs iii, and wherebyrotation of the discs --2 then rotates the discs 40-4I and the shaft 42in the same direction as that previously described.

The low spot 48 of the disc 49 which is in the groove 44 is thus swungclear of the groove and a portion of a contact surface 50 of said discis received in said groove and is engaged by the disc l while thecontact surface 5| of the disc 4| is' still engaged by the disc 2Rotation of the shaft 42 is thus continued until a low spot 49 of thedisc 4| enters the groove 44, whereupon continued axial shifting of theshaft 42, until arrested by the stop 58, spaces the contact surface 59of the disc 40 and the low spot 49 of the disc 4| from the cooperatingsurfaces of the groove 44, so as to disengage the driving connection aspreviously described. Rotation of the shaft 42 is then arrested by thestop 53 engaging the upper surface of the arm 6 when the shaft has beenrotated exactly 90.

With the shaft 42 thus fixed against further rotation, and with a lowspot 49 of the disc 4| and a portion of a contact surface 50 of the disc48 then received in the groove 44, the parts are again in position readyfor engagement of the driving connection by transverse shifting of thearm 6 in the opposite direction, to the position shown at Fig. 11.

At each transverse shifting of the arm 6* in one direction or the other,the shaft 42 is thus rotated exactly 90 in the direction of the arrow G,thereby providing corresponding step-by-step rotation of the gear 46,for driving any suitable mechanism such as an indicator. Each impulse ofan alternating current in the circuit which includes the electro-magnetlo -l l and which causes the arm 6 to be transversely shifted in onedirection or the other, thus results in a driving force being applied,for step-by-step rotation of the gear 46 in synchronism with theimpulses of said alternating current, so as to synchronously actuate anydesired mechanism which is arranged for operation by the gear 46.

When rotation of the shaft 42 is arrested, one or the other of the stops52--53 rests upon the arm 6 without frictional binding engagement sincethe driving connection which rotates the shaft is then disengaged, andconsequently rotation of the shaft is simply arrested by abutment of oneor the other of the stops against the upper surface of the arm, with noforce exerted such as would tend to tightly frictionally bind thisabutment. The upper surface 8|] of the arm 6 which is engaged by one orthe other of the stops, is disposed so that the plane of abutmentbetween the arm and either stop is substantially parallel to the planeof transverse shifting of the arm. By thus eliminating frictionalbinding engagement at the abutment of either stop against the uppersurface of the arm, with the abutment in a transverse plane asdescribed, the arm 6 is adapt ed for transverse shifting to control thedriving connection with no binding action opposing its free movement,thereby adapting the device for control by a weak force and alsoadapting it for imparting a series of rotary impulses to the shaft 42,with said series of impulses following one another with great rapidity.

As illustrated by the various modifications which have been described,the invention thus provides for applying a relatively strong drivingforce for impulse actuation of a driven element in accordance withintermittent engagement of a driving connection, with the intermittentengagement of the driving connection controlled by a series of impulseswhich may be successive impulses of an electrical current, whereby thedriven element is actuated in accordance with the impulses of saidcurrent for synchronously actuating any desired mechanism, e. g. ashutter, an indicator, or a control for making and breaking anelectrical circuit.

I claim:

1. In combination, a pair of friction discs adapted for rotation on acommon axis, means for rotating the discs, a driven element adapted foroscillation on an axis transverse to the axis of rotation of the discsand adapted for shifting transversely of its axis of oscillation and.between the friction discs, actuating means for transversely shiftingthe driven element in one direction or the other for initially engagingone end or the other of the driven element by the proximate frictiondisc so as to provide a driving connection for turning the drivenelement, said actuating means continuing said transverse shifting of thedriven element subsequent to said initial engagement so as to maintainsaid driving connection for continuing turning of the driven element,means for limiting said transverse shifting of the driven elementwhereby the driving connection at the engaged end of .the driven elementis disengaged responsive to turning of the driven element, and

means for arresting turning of the driven element thereof, therebyproviding a driving connection upon disengagement of the drivingconnection, the driven element being arranged so that when its turningis arrested upon disengagment of the driving connection at its engagedend its other end is in position ready for engagement by the proximatefriction disc upon transverse shifting of the driven element in theopposite direction.

2. In combination, a pair of toothed elements adapted for rotation on acommon axis, means for rotating said elements, a driven element adaptedfor oscillation on an axis transverse to the axis of rotation of thetoothed elements and adapted for shifting transversely of its axis of-'oscillation and between the toothed elements, ac-

tuating means for transversely shifting the driven element in onedirection or the other for engaging one end or the other of the drivenelement by a tooth of the proximate toothed element so as to provide adriving connection for turning the driven element, the transverseshifting of the driven element causing its engaged end to overlap thecooperating tooth so as to maintain said driving connection untilpredetermined turning of the driven element moves its engaged end clearof said tooth so as to disengage said driving connection, and means forarresting turning of the driven element upon disengagement of thedriving connection, the driven element being arranged so that when itsturning is arrested upon disengagement of the driving connection at itsengaged end its other end is in position for engagement by a tooth ofthe proximate toothed "element upon transverse shifting of the drivenelement in the opposite direction.

3. In combination, a driving element adapted for rotation and having aperipheral groove, means for rotating the driving element, a drivenelement adapted for rotation on an axis parallel to the axis of rotationof the driving element and having a peripheral tongue adapted for re-'ception in said groove, each side of the peripheral tongue having acontact surface interrupted by one or more low spots, actuating meansfor axial- 1y shifting the driven element in one direction or the otherfor initially engaging the contact surface at one side or the other ofthe peripheral tongue with the proximate side of the peripheral groovewhile a low spot at the other side of the peripheral tongue is receivedin the peripheral groove in spaced relation from the proximate side atthe initially engaged side of the peripheral tongue for turning thedriven element, said turning of the driven element moving the contactsurface at the other side of the peripheral tongue into the peripheralgroove for engagement with the proximate side thereof so as to provide adriving connection at said last mentioned contact surface, said turningof the driven element then moving a low spot at the initially engagedside of the peripheral tongue into the peripheral groove for spacingsaid side of the tongue from the proximate side of the groove andthereby disconnecting the driving connection at said side of theperipheral tongue, the aforesaid actuating means continuing said axialshifting of the driven element so as to disengage the driving connectionat the other side of the peripheral tongue, means for limiting saidaxial shifting with the low spot of the initially engaged side of theperipheral tongue remaining spaced from the proximate side of theperipheral groove so as to maintain disengagement of the drivingconnection at said side of the peripheral tongue, and means forarresting rotation of the driven element upon such completedisengagement of the driving connection, said means being arrangedwhereby movement of the aforesaid actuating means for axially shiftingthe driven element in the opposite direction releases the driven elementfor further rotation.

4. In combination, transmission elements each adapted for movement, saidelements being also adapted for relative shifting distinct from saidmovement of the elements, a contact surface on one of the transmissionelements, actuating means for producing said relative shifting, meansfor periodically operating said actuating means independently of saidmovement of the transmission elements, said relative shifting causingengagement of the contact surface on the said one of the transmissionelements with the other transmission element, said engagement providinga driving connection for producing said movement of one of thetransmission elements by said movement by the other transmissionelement, the transmission elements being adapted for relativedisplacement responsive tomovement thereof one by the other, and thecontact surface being adapted for disengagement from the othertransmission element responsive to said relative displacementandindependently of said relative shifting, and means operative upondisengagement of the contact surface from the other transmission elementfor arresting said movement of one of the transmission elements by theother.

5. In combination, transmission elements each adapted for movement, saidelements being also adapted for relative shifting distinct from saidmovement of the elements, a contact surface on one of the transmissionelements, actuating means for producing said relative shifting, meansfor periodically operating said actuating means adapted fordisengagement from the other transmission element responsive to saidrelative displacement and independently of said relative shifting,abutment means operative upon disengagement of the contact surface fromthe other transmission element for arresting said movement of one of thetransmission elements by the other,

'and another contact surface on one of the transmission elements adaptedfor positioning responindependently of said movement of the transsive.to said relative displacement and said rela tive shifting, forengagement with the other transmission element responsive to thetransmission elements being again relatively shifted, said lastmentioned engagement repeating the cycle of operation, and the abutmentmeans being inoperative during repetition of the cycle of operationuntil disengagement of the last mentioned contact surface from the othertransmission element.

6. In combination, transmission elements each adapted for movement, saidelements being also adapted for relative shifting in either of oppositedirections, with said relative shifting distinct from said movement ofthe elements, a contact surface on one of the transmission elements,actuating means for producing said relative shifting, means forperiodically operating said actuatingmeans independently of saidmovement of the transmission elements, the relative shifting in onedirection causing engagement of the contact surface on the said one ofthe transmission elements with the other transmission element, saidengagement providing a driving connection for producing said movement ofone of the transmission elements by said movement by the othertransmission element, the transmission elements being adapted forrelative displacement responsive to movement thereof one by the other,the contact surface being adapted for disengagement from the othertransmission element responsive to said relative displacement andindependently of said relative shifting, abutment means operative upondisengagement of the contact surface from the other transmission elementfor arresting said movement of one of the transmission elements by theother, and another contact surface on one of the transmission elementsadapted for positioning responsive to said relative displacement andsaid relative shifting, for engagement with the other transmissionelement responsive to the transmission elements being relatively shiftedin the direction opposite to that first mentioned, said last mentionedengagement repeating the cycle of operation, and the abutment meansbeing inoperative during repetition of the cycle of operation untildisengagement of the last mentioned contact surface from the othertransmission element.

7. In combination, a driving member, a driven member, said membershaving peripheral elements forming a cooperating tongue and groove, eachside of one of said peripheral elements having a contact surfaceinterrupted by one or more low spots, and actuating means for relativelyaxially shifting the driving and driven members in one direction or theother for initially engaging one or the other contact surfaces with theproximate side of the cooperating peripheral element, while a low spotwhich interrupts the other contact surface spaces said other contactsurface from that side of the cooperating peripheral element which isproximate thereto, thereby providing a driving connection at theinitially engaged contact surface for driving the driven member by thedriving member, said driving of the driven member by the driving membermoving a low spot which interrupts the initially engaged contact surfaceinto position spacing said initially engaged contact surface from thatside of the cooperating peripheral element which is proximate thereto,and moving the other contact surface so that it is in position forengagement with that side of the cooperating peripheral element which isproximate thereto.

8. In combination, a driving member, a driven member, said membershaving peripheral elements forming a cooperating tongue and groove, eachside of oneof said peripheral elements having a contact surfaceinterrupted by one or more low spots, and actuating means for relativelyaxially shifting the driving and driven members in one direction or theother for initially engaging one or the other contact surfaces with theproximate side of the cooperating peripheral element, while a low spotwhich interrupts the other contact surface spaces said other contactsurface from that side of the cooperating peripheral element which isproximate thereto, thereby providing a driving connection at theinitially engaged contact surface for driving the driven member by thedriving member, said driving of the driven member by the driving membermoving said other contact surface into engagement with that side of thecooperating peripheral element which is proximate thereto, so astoprovide a driving connection at said other contact surface forcontinuing said driving of the driven member by the driving member, saiddriving of the driven member by the driving member then moving a lowspot which interrupts the initially engaged contact surface intoposition spacing said initially engaged contact surface from that sideof the cooperating peripheral element which is proximate thereto,thereby disconnecting the driving connection at said initially engagedcontact surface, and the aforesaid actuating means continuing saidrelative axial shifting of the driving and driven members so as todisengage the driving connection at said other contact surface while thesaid low spot which interrupts the initially engaged contact surface isin position from that side of the cooperating peripheral element whichis proximate thereto.

9. In combination, transmission elements comprising a driving member anda driven member, a pair of contact surfaces on one of said elements,said surfaces being each interrupted by one or more low spots, actuatingmeans for relatively axially shifting the transmission elements forinitially engaging one or the other contact surface with the othertransmission element for driving the driven member by the drivingmember, and means for periodically operating the actuating meansindependently of driving and driven movement of the transmissionelements, said driving of the driven member by the driving member movinga low spot of the initially engaged contact surface into positionspacing said initially engaged contact surface from the othertransmission element, and moving the other contact surface so that it isin position for engagement with the other transmission element.

10. In combination, transmission elements comprising a driving memberand a driven member, a pair of contact surfaces on one of said elements,said surfaces being each interrupted by one or more low spots, andactuating means for relatively axially shifting the transmissionelements for initially engaging one or the other contact surface withthe other transmission element, while a low spot of the other contactsurface spaces said contact surface from the other transmission element,thereby providing a driving connection at the initially engaged contactsurface for driving the driven member by the driving member, saiddriving of the driven member by the driving member moving said othercontact surface into engagement with the other transmission element, soas to provide a driving connection at said other contact surface forcontinuing driving of the driven member by the driving member, saiddriving of the driven member by the driving 'member then moving a lowspot of the initially engaged contact surface into position spacing saidinitially engaged contact surface from the other transmission element,thereby discontinuing the driving connection at said initially engagedcontact surface, and the aforesaid actuating means continuing saidrelative axial shifting of the driving and driven members so as todisengage the driving connection at said other contact surface while thesaid low spot of the initially engaged contact surface is in positionspacing said initially engaged contact surface from the othertransmission element.

20 spacing said initially engaged contact surface 11. In combination,transmission elements, a driving connection between said elementsadapted for engagement by relatively axially shifting said elements inone direction or the other, the engaged driving connection driving saidelements one by the other, said driving of the elements one by the otherrelatively positioning the same for disengaging the driving connectionby continued relative axial shifting of said elements, and actuatingmeans for relatively axially shifting the transmission elements forengaging the driving connection and for then continuing said relativeaxial shiltirr for disengaging the driving connection.

12. In combination, transmission elements, a driving connection betweensaid elements adapted for engagement by relatively axially shifting saidelements in one direction or the other, the engaged driving connectiondriving said elements one by the other, said driving of the elements oneby the other relatively positioning the same for disengaging the drivingconnection by continued relative axial shifting of said elements,actuating means for relatively axially shifting the transmissionelements for engaging the driving connection and for then continuingsaid relative axial shifting for disengaging the driving connection, andmeans operative responsive to disengagement of the driving connectionfor arresting movement of that transmission element which has beendriven by the other transmission element.

13. In combination, transmission elements comprising a rotary drivingelement and an oscillatory driven element shiftable transversely of itsaxis, actuating means for transversely shifting the driven element inone direction or the other for initially engaging and turning the drivenelement by the driving element, said turning of the driven element bythe driving element causing relative displacement of said elementstending to disengage the same, the actuating means continuing saidtransverse shifting of the driving element subsequent to said initialengagement so as to maintain engagement and turning of the drivenelement by the driving element, and means for limiting said transverseshifting of the driven element whereby said relative displacement of thedriving and driven elements disengages the same.

14. In combination, transmission elements comprising a rotary drivingelement and an oscillatory driven element shiftable transversely of itsaxis, actuating means for transversely shifting the driven element inone direction or the other for initially engaging and turning the drivenelement by the driving element, said turning of the driven element bythe driving element causing relative displacement of said elementstending to disengage the same, the actuating means continuing saidtransverse shifting of the driven element subsequent to said initialengagement so as to maintain engagement and turning of the drivenelement by the driving element, and means for limiting said transverseshifting of the driven element whereby said relative displacement of thedriving and driven elements disengages the same and positions the drivenelement for reengagement by the driving element when the driven elementis transversely shifted in the opposite direction.

15. In combination, transmission elements comprising a rotary drivingelement and an oscillatory driven element shiftable transversely of itsaxis, actuating means for transversely shifting the driven element inone direction or the other for initially engaging and turning the drivenelement by the driving element, said turning of the driven element bythe driving element causing relative displacement 'of said elements fordisengaging the same, and means for arresting turning of the drivenelement upon its disengagement from the driving element.

16. In combination, transmission elements comprising a rotary drivingelement and an oscillatory driven element shit-table transversely of itsaxis, actuating means for transversely shifting the driven element inone direction or the other for initially engaging and turning the drivenelement by the driving element, said turning of the driven element bythe driving element causing relative displacement of said elements fordisengaging the same, and means for arresting turning of the drivenelement upon its disengagement from the driving element; said arrestedturning of the driven element positioning it for r'eengagement by thedriving element when the driven element is transversely shifted in theopposite direction.

17. In combination, transmission elements comprising a rotary drivingelement and an oscillatory driven element shiftable transversely of itsaxis, actuating means for transversely shifting the driven element inone direction or the other for initially engaging and turning the drivenelement by the driving element, said turning of the driven element bythe driving element causing relative displacement of said elementstending to disengage the same, the actuating means continuing saidtransverse shifting of the driven element subsequent to said initialengagement so as to maintain engagement and turning of the drivenelement by the driving element, means for limiting said transverseshifting of the driven element whereby said relative displacement of thedriving and driven elements disengages the same, and means for arrestingturning of the driven element upon its disengagement from the drivingelement, said arrested turning of the driven element positioning it forreengagement by the driving element when the driven element istransversely shifted in the opposite direction.

DELOS E. MARSH.

